Disposable absorbent article having elasticized flaps provided with leakage resistant portions

ABSTRACT

An article of manufacture is disclosed for absorbing liquids, particularly body fluids such as urine. An absorbent core is encased in an outer covering layer to which flaps are connected along the longitudinal sides. The flaps are elasticized and have a leakage resistant portion which is non-wicking, non-absorbent and liquid impermeable.

This is a continuation of application Ser. No. 510,467, filed on June30, 1983, now abandoned, which in turn is a continuation of applicationSer. No. 308,017, filed on Oct. 5, 1981, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to disposable absorbent articles in general andmore particularly relates to disposable diapers and the like. Still moreparticularly, this invention relates to disposable diapers having amultiplicity of flaps along the longitudinal sides of the absorbent corein which the flaps have an elastically contractible distal edge, a fixededge and a non-wicking, non-absorbent, liquid impermeable leakageresistant member interposed between the distal and fixed edges on theliquid contacting surface.

Disposable absorbent articles are well known and have many uses. Forexample, disposable diapers are intended to absorb and contain urine;bandages are intended to absorb and contain blood and other bodyexudates; while catamenial pads are intended to absorb and retainmenstrual fluids. In each instance, the disposable absorbent articleabsorbs and retains a liquid, thereby preventing that liquid fromsoiling, wetting, or otherwise contaminating the vicinity surroundingthe point of liquid discharge. For example, U.S. Pat. No. Re. 26,151which issued on Jan. 31, 1967 to R. C. Duncan et al. entitled"Disposable Diaper" teaches a disposable diaper intended to absorb urineand prevent the wetting of the wearer's clothing.

Disposable absorbent articles should perform without leaking and severalconcepts have been proposed to improve the liquid containmentcharacteristics of disposable absorbent articles such as disposablediapers. U.S. Pat. No. 3,999,548 entitled "Disposable Diaper HavingFluid Trap" which issued to J. Hernandez on Dec. 28, 1976 teaches thatthe liquid containment characteristics of a diaper can be improved bysecuring sealing strips of waterproof material to the face sheet of thediaper. Alternatively, U.S. Pat. No. 3,860,003 entitled "ContractibleSide Portions For A Disposable Diaper" which issued to K. B. Buell onJan. 14, 1975 and U.S. Pat. No. 4,050,462 entitled "Disposable DiaperWith Elastically Constricted Crotch Section" which issued to L. S. Woonet al. on Sept. 7, 1977 both teach a concept for reducing liquid leakagewhich involves providing an elastic member in a disposable diaper. Theelastic member is positioned so that when the diaper is worn, the diaperis drawn snugly about the legs of the wearer. The elastic causes thediaper to form a seal about the leg of the wearer thereby preventingliquid from leaking out of the diaper.

The disposable absorbent articles of the prior art lack the aspects ofthe present invention whereby an improvement in the liquid containmentcharacteristics is obtained by providing elastically contractible flapsalong the longitudinal sides of the article which flaps have a leakageresistant portion which is non-wicking, non-absorbent, and liquidimpermeable.

It is therefore an object of the present invention to provide adisposable absorbent article having improved liquid containmentcharacteristics.

A further object of the present invention is to provide a disposableabsorbent article having elastically contractible flaps provided with aleakage resistant portion which is non-wicking, non-absorbent, andliquid impermeable.

These and other objects of the invention will be more readily apparentwhen considered in reference to the following description and when takenin connection with the accompanying drawings.

SUMMARY OF THE INVENTION

According to the present invention, a disposable absorbent article suchas a diaper is manufactured such that a liquid absorbent core is encasedin an outer covering layer having a liquid permeable topsheet portionand a liquid impermeable backsheet portion. The disposable absorbentarticle is provided with a multiplicity of flaps which fit about thelegs of the wearer when the diaper is worn. The flaps have a fixed edgeconnected to the outer covering layer, an elasticized distal edge spacedfrom the fixed edge, and a liquid contacting surface across which liquidmust flow to move from the fixed edge to the distal edge.

A leakage resistant portion which is non-wicking, non-absorbent andliquid impermeable is interposed on the liquid contacting surface of theflaps, between the fixed and distal edges. Thus, in order for liquid toflow or wick from the point of discharge to the distal edge where liquidleakage about the legs can occur it is necessary for the liquid to moveacross the leakage resistant portion. The leakage resistant portion isnon-wicking and non-absorbent which characteristics prevent liquid fromreaching the distal edge of the flap from which leakage from the diapercan occur.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a disposable diaper which incorporatesthe present invention and which is Z-folded and ready to be placed on aninfant.

FIG. 2 is a partially cut away perspective view of the disposable diaperof FIG. 1 prior to being Z-folded and contracted.

FIG. 3 is a cross-sectional view of the diaper of FIG. 2 taken alongline 3--3.

FIG. 4 is a cross-sectional view of an alternatively preferredembodiment of the present invention taken along a line corresponding toline 3--3.

FIG. 5 is a cross-sectional view of an alternatively preferredembodiment of the present invention taken along a line corresponding toline 3--3.

FIG. 6 is a cross-sectional view of an alternatively preferredembodiment of the present invention taken along a line corresponding toline 3--3.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to the figures, there is shown a preferred embodiment ofthe present invention as it would be used in a disposable absorbentarticle and, in particular, as it would be used in a disposable diaper.As used herein, the term disposable absorbent article refers to articleswhich absorb and contain liquid, and more specifically refers toarticles which are placed against or in proximity to the human body toabsorb and contain the various liquids discharged therefrom (e.g.,blood, menses, urine, etc.), and further which articles are intended tobe discarded after a single use (i.e., they are not intended to belaundered or otherwise restored and reused). A "diaper" is a garmentgenerally worn by infants or incontinent persons, which is drawn upbetween the legs and fastened about the waist of the user. It should beunderstood, however, that the present invention is also applicable foruse in other disposable absorbent articles such as bandages, catamenialpads, and the like.

FIG. 1 is a perspective view of a diaper 10 having a Z-folded sideconfiguration and incorporating the features of the present invention.As shown in FIG. 1 the diaper 10 is in condition for placement on awearer. In general, the crotch portion 13 of the diaper 10 is placedbetween the wearer's legs and the front and back waist portions 15 and17 respectively, are joined together by adhesive tapes 56 so as toencircle the wearer's waist and to hold the diaper 10 in place. Whilethe present invention will be described with reference to a diaperhaving a Z-folded side configuration, it should be understood thatdiaper configurations and constructions other than those specificallydescribed, such as C-folded and unfolded side configurations, may alsoincorporate the features of the present invention.

To simplify the description of the present invention the diaper 10 ofFIG. 1 is shown in FIG. 2 in a partially cut-away perspective view priorto its being Z-folded, contracted, and placed on the diaper wearer. Asseen in FIG. 2, a preferred disposable diaper 10 basically comprises anouter covering layer 11 and an absorbent core 14. While the outercovering layer 11 and the absorbent core 14 may be assembled in avariety of well known configurations, such as are described generally inU.S. Pat. No. Re. 26,151 entitled "Diaper" which issued to R. C. Duncanet al. on Jan. 31, 1967, and in U.S. Pat. No. 3,860,003 entitled"Contractible Side Portions For Disposable Diaper" which issued to K. B.Buell on Jan. 14, 1975, which patents are incorporated herein byreference, a preferred construction of the diaper 10 will now bedescribed.

As can be seen in FIGS. 2 and 3, a preferred outer covering layer 11encases and contains the absorbent core 14 and preferably has a topsheetportion 12 and a backsheet portion 16 which are joined together in anysuitable matter. As used herein, the term "joined" encompassesconfigurations whereby the topsheet portion 12 is directly joined to thebacksheet portion 16 by affixing the topsheet portion 12 directly to thebacksheet portion 16 and configurations whereby the topsheet portion 12is indirectly joined to the backsheet portion 16 by affixing thetopsheet portion 12 to intermediate members which in turn is affixed tothe backsheet portion 16. In the preferred embodiment of FIGS. 2 and 3,the topsheet portion 12 and the backsheet portion 16 are joined directlyto each other.

The absorbent core 14 may be any means which is generally compressible,conformable, non-irritating to the wearer's skin, and which is capableof absorbing and retaining liquids. A preferred absorbent core 14 hasfirst and second opposed faces 20 and 22 respectively, and comprises anabsorbent layer 24 and first and second tissue layers 26 and 28respectively. The first and second tissue layers 26 and 28 overlay themajor surfaces of the absorbent layer 24 to form first and secondopposed faces 20 and 22. The outer periphery of the absorbent core 14forms a peripheral edge 50 having first and second longitudinal sideedges 52 and 54 respectively.

The absorbent layer 24 may be manufactured in a wide variety of sizesand shapes (e.g., rectangular, hourglass, etc.) and from a wide varietyof liquid absorbent materials commonly used in disposable absorbentarticles, such as comminuted wood pulp which is generally referred to asabsorbent fluff. Other liquid absorbing materials can also be used forthe absorbent layer 24, such as a multiplicity of plies of crepe,cellulose wadding, absorbent foams or sponges, or any equivalentmaterial. Further, the size and absorbent capacity of the absorbentlayer 24 may be varied to accommodate wearer's ranging from infants toadults. The preferred embodiment illustrated in FIGS. 2 and 3 has arectangular absorbent layer 24 and is intended for infants of from about12 pounds to about 23 pounds (about 5 kilograms to about 10 kilograms).The absorbent layer 24 is, therefore, absorbent fluff approximately 12inches (31.8 centimeters) wide by 16 inches (40.6 centimeters) longhaving an absorbent capacity of from 8 to 16 grams of water per gram ofabsorbent. Accordingly, the absorbent fluff used in the preferredembodiment shown in FIGS. 2 and 3 weighs approximately from 30 to 56grams. It should be understood, however, that the size, shape, and totalabsorbent capacity of the absorbent core 14 may be varied to accommodatewearers ranging from infants to adults. Therefore, other dimensions andeven other shapes (e.g., hourglass) may also be used for the absorbentcore 14.

The tissue layers 26 and 28 improve the tensile strength of theabsorbent core 14 and reduce the tendency of the absorbent layer 24 tosplit, lump or ball when wetted. The tissue layers 26 and 28 also helpto improve lateral wicking of absorbed liquids, thereby providing a moreeven distribution of liquids throughout the absorbent core 14. While anumber of materials and manufacturing techniques may be used tomanufacture the tissue layers 26 and 28, satisfactory results have beenobtained with sheets of tissue paper having a basis weight of from about10 pounds per 3,000 square feet (16 grams per square meter) and havingan air permeability of about 100 cubic feet per minute per square foot(30.5 cubic meters per minute per square meter) over a 1/2 inch (12.8millimeter) water pressure drop. While the tissue layers 26 and 28 arepreferably coterminous with the absorbent layer 24, they may havedifferent dimensions, a different configuration, or they may be omittedentirely.

The second tissue layer 28 is superimposed on the backsheet portion 16and is preferably attached thereto by attachment means (not shown) suchas those well known in the art. For example, the absorbent core 14 canbe secured to the backsheet portion 16 by a uniform continuous layer ofadhesive, a patterned layer of adhesive, or an array of separate linesor spots of adhesive. An adhesive which has been found to besatisfactory is manufactured by Eastman Chemical Products Company ofKingsport, Tenn. and marketed under the tradename Eastobond A-3.

The backsheet portion 16 is impervious to liquids and is preferablymanufactured from a thin plastic film, although other flexible liquidimpervious materials may also be used. The backsheet portion 16 preventsthe liquids contained in the absorbent core 14 from wetting articleswhich contact the diaper, such as bedsheets and undergarments.Polyethylene films having a thickness of from about 0.0005 to about0.002 inches (0.0012 to 0.0051 centimeters) have been used for thebacksheet portion 16 in a preferred embodiment with satisfactoryresults. As used herein, the term "flexible" refers to materials whichare compliant and which will readily conform to the general shape andcontours of the human body. A suitable polyethylene film is manufacturedby Monsanto Chemical Company and marketed in the trade as film No. 8020.

The topsheet portion 12 is compliant, soft feeling, and non-irritatingto the wearer's skin. Further the topsheet portion 12 is liquidpermeable, permitting liquids to readily penetrate through itsthickness. A suitable topsheet 12 may be manufactured from a wide rangeof materials such as porous foams, apertured plastic films, naturalfibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyesteror polypropylene fibers) or from a combination of natural and syntheticfibers and prevents the wearer of the diaper 10 from contacting theabsorbent core 14.

A particularly preferred topsheet portion 12 comprises by weight about65 percent staple length polyester fibers having a denier of about 1.5,such as Kodel-type 411 polyester fibers marketed by Tennessee EastmanCorporation of Kingsport, Tenn.; about 15 percent staple length crimpedrayon fibers having a denier of about 1.5; and about 20 percent acryliccopolymer binder such as Celanese CPE 8335 marketed by CelaneseCorporation of Charlotte, N.C. As used herein, the term "staple lengthfibers" refers to those fibers having a length of at least 5/8 inches(15.9 millimeters).

Clearly, there are a number of manufacturing techniques which may beutilized to manufacture the topsheet portion 12. For example, thetopsheet portion 12 may be woven, non-woven, spunbonded, carded or thelike. A preferred topsheet portion 12 is carded, saturated with a bindersolution, dried and cured by means well known to those skilled in theart. Preferably, the topsheet portion 12 has a basis weight range offrom about 18 to about 22 grams per square yard. A preferred topsheetportion 12 is further characterized by a minimum wet tensile strength ofat least about 400 grams per centimeter in a machine direction and atleast about 55 grams per centimeter in a cross machine direction.

The backsheet portion 16 is superimposed on the second opposed face 22of the absorbent core 14 and has dimensions generally larger than thoseof the absorbent core 14. The topsheet portion 12 is superimposed onfirst opposed face 20 of the absorbent core 14 and is coterminous withthe first and second longitudinal side edges 52 and 54, respectively,but is longer than the absorbent core 14. The longitudinal margins 30 ofthe backsheet portion 16 are folded onto and affixed to the topsheetportion 12 along the longitudinal seams 32 in any suitable manner suchas by the use of adhesives. A suitable adhesive is manufactured byNational Starch Corporation of Bridgewater, N.J. and marketed under thetradename Instant Lock 34-2933, although other adhesives as are wellknown may also be used. As best seen in FIG. 2, transverse edges 34 ofthe topsheet portion 12 are folded onto the second opposed face 22 ofthe absorbent core 14 and affixed to the backsheet portion 16 alongtransverse seams (not shown). The absorbent core 14 is, therefore,encased within the outer covering layer 11 which comprises the backsheetportion 16 and the topsheet portion 12, the backsheet portion 16, andthe absorbent core 14 may be assembled into a disposable diaper is givenin the hereinbefore referenced U.S. Pat. No. Re. 26,151 entitled"Disposable Diaper" which issued to R. C. Duncan et al. on Jan. 31,1967.

Liquid discharged onto the diaper 10 while it is being worn will tend tobe distributed throughout the diaper 10. A a result of the liquiddistribution some of the liquid will move toward segments of the diaper10 from which leakage can occur. The location of these segments and thespecific means by which leakage occurs will depend on the particularconstruction used for the diaper 10. In general, however, liquid leakagefrequently occurs at those segments of the diaper 10 which are fittedabout the legs of the diaper wearer.

The figures illustrate a preferred embodiment and alternativelypreferred embodiments of the present invention in which liquid leakagearound the legs of the diaper wearer is to be reduced. Accordingly, thediaper 10 illustrated in FIGS. 2 and 3 is provided with a multiplicityof flaps 37 positioned so as to encircle the legs of the wearer when thediaper is worn. While it is not essential that the legs be completelyencircled, the preferred embodiment shown in FIG. 2 has flaps 37traversing the entire length of the diaper 10.

The flaps 37 are thin, flexible bands having a fixed edge 40, a distaledge 42, and a liquid contacting surface 43. The fixed edge 40 and thedistal edge 42 are in spaced relation to each other and define the widthof the flaps 37. The fixed and distal edges 40 and 42 may be parallel,nonparallel, rectilinear or curvilinear. Preferably, however, the distaland fixed edges 42 and 40 are parallel and rectilinear thereby impartinga uniform width to the flaps 37. The liquid contacting surface 43 is themajor surface the longitudinal sides of which are bounded by the fixedand distal edges 40 and 42 by the fixed and distal edges 40 and 42 andacross which surface urine (as hereinafter defined) must flow to movefrom the fixed edge 40 to the distal edge 42.

The preferred diaper 10 illustrated in FIG. 2 is provided with a firstflap 38 and with a second flap 39 each having a fixed edge 40 connectedto the outer covering layer 11 at the first longitudinal side edge 52and at the second longitudinal side edge 54 respectively. The term"connected" includes any means for affixing the flaps 37 to the outercovering layer 11 and encompasses means whereby the flaps 37 are madeintegral with the outer covering layer 11 (i.e., the flaps 37 are aseparate element affixed to the outer covering layer 11) and meanswhereby the flaps 37 are unitary with the outer covering layer 11 (i.e.,the flaps 37 have at least one continuous and undivided element incommon with the outer covering layer 11). In the preferred diaperconstruction shown in FIGS. 2 and 3, the flaps 37 are connected to thecovering layer 11 adjacent to the first and second longitudinal sideedges 52 and 54 of the absorbent core 14 so that when the diaper is wornthe flaps 37 will encircle the legs of the wearer. If other diaperconstructions are used other placements of the flaps 37 may benecessary.

The distal edge 42 is elastically contractible having a stretched length(i.e., a length when subjected to a tensile force sufficient to overcomethe contractive forces of the elastic element 44) which is at leastabout 110% of its contracted length (i.e., the length of the distal edge42 when not tensile forces are applied and the contractive forces of theelastic element 44 are allowed to contract the distal edge 42). Thus,the distal edge 42 is the line spaced farthest from the fixed edge 40(which distance is measured along the liquid contacting surface 43 ofthe flaps 37) along which elastic contraction occurs.

The distal edge 42 is preferably displaced from the absorbent core 14 adistance sufficient to permit the flaps 37, which are flexible, to begathered about the legs of the wearer without major gaps being formedbetween the flaps 37 and the wearer's legs. As used herein, the term"displaced" includes distal edges 42 which are displaceable from theabsorbent core 14. In other words, if the distal edge 42 may assume morethan one position relative to the absorbent core 14 with equal facilitythen that distal edge 42 is displaceable and included in the term"displaced" even though the distal edge 42 may assume a positionadjacent to the absorbent core 14 at some times. The distance from thedistal edge 42 to the absorbent core 14 is measured along a line drawnfrom the distal edge 42 to the closest part of the absorbent core 14when the distal edge 42 is positioned so as to be spaced from theabsorbent core 14 as far as possible. Preferably, the distal edge 42will be displaced from the absorbent core 14 a distance of at leastabout 0.25 inches (6.3 mm). Most preferably the distal edge 42 will bedisplaced at least about 0.50 inches (13 mm) and still more preferablyat least about 0.75 inches (19 mm).

While the flaps 37 may be manufactured from an elastic material orotherwise made to be elastically contractible the required elasticity ispreferably provided by an elastic element 44. The elastic element 44 isaffixed to the flaps 37 in an elastically contractible condition so thatin a normally unrestrained configuration, the elastic element 44effectively contracts or gathers the flap material adjacent to theelastic element 44. The placement of the elastic element 44 willdetermine the location of the distal edge 42 as hereinbefore described.The elastic element 44 may be affixed to the flaps 37 in an elasticallycontractible condition in at least two ways. For example, the elasticelement 44 may be stretched to its stretched condition and fixed to theflaps 37 while the flaps 37 are in an uncontracted condition.Alternatively, the flaps 37 may be contracted, for example, by pleating,and the elastic element 44 fixed to the contracted flaps 37 while theelastic element 44 is in its relaxed or unstretched condition.

The elastic element 44 preferably develops a skin contact pressure inuse of from about 0.1 to about 2.5 pounds per square inch (about 0.7 toabout 17 kpa). A skin contact pressure within that range is acceptableto provide continued contact of the flaps 37 with the infant's thighwithout exerting a pressure which detrimentally indents or marks theskin. To provide the proper skin contact pressure, the elastic element44 will preferably have a contractional force in its stretched conditionin the range of from about 10 to about 200 grams and most preferably inthe range of from about 20 to about 100 grams. The elastic element 44should provide such a contractional force and thus establish itsstretched condition at an elongation from its relaxed state in the rangeof from about 50 to about 400 percent and most preferably in the rangeof from about 125 to about 300 percent.

One elastic member 44 which has been found to work well is an elastictape having a cross-section of 0.007 inches by 0.06 inches and made fromnatural rubber which is available from East Hampton Rubber Company andidentified by them as L-1900 Rubber Compound. The elastic tape producesa contractual force of about 50 grams when stretched 150 percent fromits relaxed condition. The rubber tape was used as the elastic element44 in the preferred embodiment of FIGS. 2 and 3 and was stretched 150percent from its relaxed condition to place it in its stretchedcondition, i.e., its maximum stretched length as allowed by thematerials used for the flaps 37 when attached to the flaps 37, and has atension therewithin of about 50 grams.

The elastic element 44, as shown in FIGS. 2 and 3, is operativelyassociated with the flaps 37 by securing it to the flaps 37 with anelastic attachment means (not shown). The elastic attachment meansshould be flexible and of sufficient adhesiveness to hold the elasticelement 44 in its stretched condition substantially indefinitely. Onematerial which has worked as a flexible elastic attachment means is hotmelt adhesives such as marketed by Findley Adhesives, Inc., Elm Grove,Wis., under the tradename Findley Adhesives 691-336. A more detaileddescription of how the elastic element 44 may be positioned and securedto the diaper 10 is given in the hereinbefore referenced U.S. Pat. No.3,860,003 entitled "Contractible Side Portions For Disposable Diaper"which issued to K. B. Buell on Jan. 14, 1975. The elastic element 44need not necessarily be secured to the flap 37 along its entire length,but may instead, for example, be attached at least or only at its twoends and be operatively associated with the flap for the remainder ofits length by extending through a sleeve within the flap or loopsintegral with the flap.

In the preferred embodiment illustrated in FIG. 2 the flaps 37 areunitary with the outer covering layer 11. More specifically, thebacksheet portion 16 is sufficiently wide so that the material used forthe backsheet portion 16 extends beyond the longitudinal seams 32. Inthis embodiment, the material used for the backsheet portion 16 is thesame as that used for the flaps 37 with the edge of the backsheetportion material adjacent the longitudinal seams 32 forming the fixededge 40 of the flaps 37.

The liquid contacting surface 43 of each flap 37 is provided withleakage resistant portion 48 (FIG. 3). The leakage resistant portion 48is a portion of the flaps 37 positioned between the distal edge 42 andthe fixed edge 40 of the flaps 37. The leakage resistant portion 48retards the movement of liquid from the fixed edge 40 of the flaps 37 tothe distal edge 42 of the flaps 37. The leakage resistant portion 48thereby provides an obstacle in the path followed by liquid as it tendsto move across the liquid contacting surface 43 from the point ofdischarge toward the distal edge 42 from which liquid leakage can occur.Accordingly, the leakage resistant portion 48 is non-wicking (i.e.,liquid contacting the leakage resistant portion 48 will not cross theleakage resistant portion 48 due to capillary liquid transport),non-absorbent (i.e., liquid is not retained by the leakage resistantportion 48 and is therefore free to flow back toward the absorbent core14), and liquid impermeable. Further, the leakage resistant portion 48is positioned and dimensioned such that liquid will not pass the leakageresistant portion 48 in normal use of the diaper 10.

In the preferred embodiment illustrated in FIGS. 2 and 3 the leakageresistant portion 48 is a strip of polyethylene film of the same type asused for the backsheet portion 16. Thus, the leakage resistant portion48 will neither absorb, nor wick liquid. In addition, the leakageresistant portion 48 is impermeable to liquid; thus, liquid will notpass through the thickness of the leakage resistant portion 48 undernormal usage and pressures.

Preferably, the leakage resistant portion 48 has a length which extendsthe entire length of the flaps 37 and a width of at least about 0.125inches (3 mm). Other dimensions may, however, also be used. For example,the leakage resistant portion 48 may have a length different from thelength of the flaps 37. In addition, a variety of widths may be used forthe leakage resistant portion 48. While the width of the leakageresistant portion 48 is preferably at least about 0.125 inches (3 mm),it is more preferably at least about 0.25 inches (6 mm) and still morepreferably at least about 0.50 inches (12 mm). The larger the width ofthe leakage resistant portion 48 the less likely liquid is to bridge theleakage resistant portion 48 and thus leak out of the diaper 10.

In use, the diaper 10 is placed between the legs of the diaper wearerand fastened about the wearer's waist using any suitable means such asadhesive tapes 56 as is well known. When the diaper 10 of the presentinvention is applied to a wearer, it exhibits improved liquidcontainment characteristics. While not wishing to be bound by any onetheory it is believed that the improved liquid containmentcharacteristics are achieved in the following manner.

As urine is discharged onto the topsheet portion 12 some of the urinepenetrates the topsheet portion 12 and is absorbed by the absorbent core14 (hereinafter referred to as absorbed urine), some of the urine flowson the surface of the topsheet portion 12 (hereinafter referred to assurface urine), some of the urine is absorbed by and wicks laterallythrough the topsheet portion 12 and some of urine flows into thecapillary channel formed at the interface between the topsheet portion12 and the skin of the diaper wearer.

The absorbed urine migrates throughout the absorbent core 14 moving fromthe point of discharge (i.e., the crotch area 13) toward the peripheraledge 50 of the absorbent core 14. Eventually, the urine will reach thefirst and second longitudinal side edges 52 and 54 respectively. Sincethe absorbed urine which encounters the leakage resistant portion 48 isnot absorbed by and cannot wick into the flaps 37 the absorbed urine iseffectively prevented from leaking out of the diaper 10 at thelongitudinal side edges 52 and 54 respectively.

The surface urine, likewise, moves from the point of discharge towardthe first and second longitudinal side edges 52 and 54 respectively.Surface urine which contacts the leakage resistant portions 48 is notabsorbed. In normal use the gravitational forces will tend to cause thesurface urine to drain back toward the absorbent core 14. The surfaceurine which does cross the leakage resistant portion is retarded fromleaking out of the diaper by the sealing affect achieved by the elasticmember 44 as it draws the flaps 37 about the legs of the diaper wearer.

The distal edge 42 of the flaps 37 is elastically contractible so thatwhen the diaper 10 is worn the distal edge 42 is drawn about thewearer's legs. The fixed edge 40 normally sags away from the wearer'slegs thereby forming a gap between the leakage resistant portion 48 andthe skin of the wearer. Liquid flowing along the capillary channelformed between the topsheet portion 12 and the skin of the diaper weareris prevented from bridging the leakage resistant portion 48 by thediscontinuity in the capillary channel at the leakage resistant portion48. In this manner, liquid is prevented from leaking from the diaper 10.

Finally, urine which is absorbed interstitially by the topsheet portion12 wicks laterally through the topsheet portion 12 toward first andsecond longitudinal side edges 52 and 54. As in the instance of thesurface urine, the urine absorbed by the topsheet portion 12 encountersthe leakage resistant portion 48 which is non-wicking. The urineabsorbed by the topsheet portion is thereby prevented from reaching thedistal edge 42 from which leakage can occur.

It will be understood by those skilled in the art that the presentinvention has been described with reference to exemplary embodiments andthat variations or modifications can be effected in the describedembodiments without departing from the spirit and scope of theinvention.

As seen in FIG. 4, for example, the flaps 37 may each be utilized asintermediate members 62, as hereinbefore described, to indirectly jointhe topsheet portion 12 and the backsheet portion 16. FIGS. 4, 5, and 6are crosssectional views of alternatively preferred embodiments of thepresent invention taken along lines corresponding to line 3-33 of FIG.2. While only one edge of the diaper is shown in and described withreference to FIGS. 4, 5, and 6 it should be understood that the edges ofthe diaper 10 are essentially mirror images of each other.

With reference to FIG. 4 it can be seen that the flaps 37 are formed byextending the material used for the backsheet portion 16 beyond thefirst longitudinal side edge 52 of the absorbent core 14 and affixingthe edge 64 of the material used for the backsheet portion 16 to thetopsheet portion 12. The edge 64 thus coincides with the fixed edge 40.The elastic element 44 is secured to the distal edge 42 and the liquidcontacting surface 43 is positioned between the fixed and distal edges40 and 42.

The leakage resistant portion 48 of the liquid contacting surface 43 ispositioned between the distal edge 42 and the fixed edge 40. Since theentire flap 37 of the alternatively preferred embodiment of FIG. 4 ismanufactured from the same material sued for the backsheet portion 16,the leakage resistant member 48 extends from the fixed edge 40 to thedistal edge 42.

FIG. 5 shows an alternatively preferred embodiment in which the flaps 37are utilized as an intermediate member 62 to indirectly join thetopsheet portion 12 and the backsheet portion 16. The flaps 37 areformed by extending the material used for the topsheet portion 12 beyondthe first longitudinal side edge 52 of the absorbent core 14 andaffixing the edge 66 of the material used for the topsheet portion 12 tothe backsheet portion 16.

The marginal portion 68 of the material used for the topsheet portion 12is treated so as to be liquid impermeable, non-absorbent, andnon-wicking. While such treatments are well known in the art a suitabletreatment is obtained by applying a food grade paraffin wax such as ismarketed by Boron Oil Co., Cleveland, Ohio, under the tradename BoronWax.

The treated marginal portion 68 forms the leakage resistant portion 48of the liquid contacting surface 43. As can be seen in FIG. 5 the fixededge 40 coincides with the inward edge of the marginal portion 68 whilethe distal edge 42 is spaced therefrom. The elastic element 44 isaffixed to the flaps 37 at the distal edge 42.

FIG. 6 shows an alternatively preferred embodiment in which the flaps 37are provided with a facing sheet 70. In this embodiment, the materialused for this backsheet portion 16 extends beyond the first longitudinalside edge 52 of the absorbent core 14 to form flaps 37 which are unitarywith the backsheet portion 16. The topsheet portion 12 is directlyjoined to the backsheet portion.

The fixed edge 40 of the flaps 37 is connected to the outer coveringlayer 11 and the elastic element 44 is affixed at the distal edge 42. Toprevent direct contact between the elastic element 44 and the skin onthe wearer a facing sheet 70 is affixed to the distal edge 42. Thefacing sheet 70 may be of any flexible material which is non irritatingto the skin. In the preferred embodiment illustrated the facing sheet 70was manufactured from the same material as was used for the topsheetportion 12.

The leakage resistant portion 48 of the liquid contacting surface 43 ispositioned between the fixed edge 40 and the distal edge 42.

We claim:
 1. A disposable diaper comprising:an outer covering layer; anabsorbent core means for absorbing liquid, said absorbent core meansbeing encased in said outer covering layer, said absorbent core meanshaving a peripheral edge comprising a first longitudinal side edge and asecond longitudinal side edge; a multiplicity of flaps, each of saidflaps having a fixed edge, a distal edge in spaced relation to saidfixed edge, and having a liquid contacting surface the longitudinalsides of which are bounded by said fixed and said distal edges, one ofsaid flaps having said fixed edge connected to said outer covering layerat said first longitudinal side edge of said absorbent core means andone of said flaps having said fixed edge connected to said outercovering layer at said second longitudinal side edge, said flaps havinga leakage resistant portion interposed on said liquid contacting surfacebetween said fixed edge and said distal edge, said distal edge beingdisplaced from said absorbent core mean, said leakage resistant portionbeing non-absorbent, and liquid impermeable; and an elastic element,said elastic element being operatively associated with said distal edgeof said flaps and secured in an elastically contractible condition tosaid flap at least at its two ends to render said distal edge of saidflaps elastically contractible so that said elastic element effectivelycontracts or gathers the flap material.
 2. The disposable diaper ofclaim 1 wherein said outer covering layer comprises a topsheet portionand a backsheet portion, said topsheet portion being joined togetherwith said backsheet portion.
 3. The disposable diaper of claim 2 whereinsaid leakage resistant portion has a width of at least about 0.125inches.
 4. The disposable diaper of claim 3 wherein said distal edge isdisplaced from said absorbent core means a distance of at least about0.25 inches.
 5. The disposable diaper of claim 1 wherein said elasticelement is secured to said flap only at its two ends.
 6. The disposablediaper of claim 1 wherein said elastic element is secured to said flapalong its entire length.